Lens & Field of View
Mount height, tilt and the blind spot under the camera, with pixel density at the target.
Camera
Optical format from the datasheet. Width and height come from the format diagonal.
Mounting
Ground distance from the pole or wall to where the person stands
Height on the target to aim at, such as face height
Results
Fix the highlighted values to see results.
Side view
Tilt down
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Blind spot
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Pixel density at target
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Vertical FOV
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Far edge on ground
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IEC 62676-4 level
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Tilt = atan((mount height − target height) ÷ distance). The blind spot is where the bottom edge of the view meets the ground: mount height ÷ tan(tilt + vertical FOV ÷ 2). Pixel density uses the slant range to the target. Levels: Monitor 12.5, Detect 25, Observe 62.5, Recognize 125, Identify 250 px/m.
Questions
How do I find the camera tilt angle?
Tilt down from horizontal is the arctangent of the mount height minus the target height, divided by the ground distance to the target.
What is the blind spot under a camera?
It is the ground between the mount and where the bottom edge of the vertical field of view reaches the floor. A higher mount or a longer lens makes it bigger; more tilt makes it smaller.
Why does pixel density drop when the camera is mounted higher?
The camera looks along the slant range, which is longer than the ground distance, so the scene is wider where it meets the target and each pixel covers more of it.
Which pixel density levels are used?
IEC 62676-4: Monitor 12.5, Detect 25, Observe 62.5, Recognize 125 and Identify 250 pixels per meter.